what is the main difference between difference between using nonatomic lseek and O

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Top Forums Programming what is the main difference between difference between using nonatomic lseek and O_APPEND Post 302715083 by jim mcnamara on Saturday 13th of October 2012 06:36:52 PM

10-13-2012

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O_APPEND guarantees that every write to the file will be at the end of the file. lseek guarantees that the file pointer is positioned to the current EOF of the file. It does not guarantee that subsequent writes will be at the end of the file.

The above is something that you only worry about when multiple processes or threads are writing to one file.

Neither guarantees any kind of sequence of I/O writes when there are multiple writers. If you need that, then you have to resort to something like SYSV semaphores for multi-process apps or mutxes in the case of multi-threaded apps.

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LEARN ABOUT OPENSOLARIS

difftime

difftime(3C)						   Standard C Library Functions 					      difftime(3C)

NAME

       difftime - computes the difference between two calendar times

SYNOPSIS

       #include <time.h>

       double difftime(time_t time1, time_t time0);

DESCRIPTION

       The difftime() function computes the difference between two  calendar times.

RETURN VALUES

       The difftime() functions returns the difference (time1-time0) expressed in seconds as a double.

USAGE

       The difftime() function is provided because there are no general arithmetic properties defined for type time_t.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ctime(3C), attributes(5), standards(5)

SunOS 5.11							    24 Jul 2002 						      difftime(3C)

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